How many deck boards for a 10×10 deck?
Quick Answer
A 10×10 foot deck (100 sq ft) requires approximately 20 boards of 5/4×6×10 decking (10-foot boards across 10-foot span) or 14 boards of 5/4×6×12 laid in the other direction. With 10% waste, order 22–25 boards. This is for decking only — add rim boards, joists, and posts separately.
Quick Reference Table
| Board size | Deck boards for 10×10 deck |
|---|---|
| 5/4×6×10 (run parallel) | 20 boards + 10% = 22 |
| 5/4×6×12 | 14 boards + 10% = 16 |
| 2×6×10 (thicker) | 20 boards + 10% = 22 |
| Composite 1"×6×12 | 14 boards + 10% = 16 |
How to Calculate It Yourself
- 1
Determine the deck area: 10 × 10 = 100 sq ft.
- 2
A 5/4×6 board has a nominal 6" width; actual face width is 5.5".
- 3
With 1/8" gap between boards, effective width per board = 5.625".
- 4
For 10 ft span: 120" ÷ 5.625" = 21.3 → 22 boards.
- 5
Add 10% for waste and end cuts: 22 × 1.10 = 25 boards.
Pro Tip
Buy boards in the longest length that avoids a seam on your deck surface. Seams on deck boards are a common weak point — full-length boards with no butt joints are stronger and look better.
Assumptions to Check
Before ordering materials, confirm the dimensions, product coverage, waste factor, and local installation requirements for your project. Manufacturer coverage tables and local code rules can change the final quantity, especially for structural work, exterior projects, and irregular layouts.
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